Umami
What is Umami?
Umami is often described as the fifth basic taste, alongside sweet, sour, salty, and bitter. It is a Japanese word that translates to "pleasant savory taste" or "deliciousness" in English. Umami is known for its savory, meaty, and mouthwatering characteristics. Umami taste is typically experienced when certain compounds activate specific taste receptors on the tongue.
Sources of Umami
Amino Acids
Amino acids are the building blocks of proteins. Although proteins themselves are tasteless, the amino acids that compose them have different tastes, including sweet, bitter, and umami. Glutamic acid, which is found in kombu seaweed, vegetables, and fermented foods, is a prominent amino acid that contributes to the umami taste. Certain peptides, small compounds of amino acids, also add to umami.
Nucleic Acids
Nucleic acids contain phosphates and are composed of nucleotides. Adenosine triphosphate (ATP), a well-known source of energy in living organisms, belongs to this group. Umami substances in the nucleic acid system include inosinic acid, which is abundant in dried sardines, bonito flakes, fish, and meat, and guanylic acid, which is plentiful in dried mushrooms.
Organic Acids
Organic acids are carbon compounds that do not contain nitrogen. Some well-known organic acids include acetic acid, citric acid, lactic acid, and succinic acid. Among these, succinic acid, which is abundant in shellfish, is known to exhibit umami taste.
How Umami Evolves in Fish
Inosinic Acids from ATPs
When a fish dies, the metabolic processes in its body cease, and biochemical reactions start to take place. One of these reactions involves the breakdown of ATP, which is a molecule that serves as an energy carrier in living organisms. ATP is present in the muscles of the fish, and after harvest, it begins to degrade.
As ATP breaks down, it undergoes a series of enzymatic reactions, leading to the formation of inosinic acid. Inosinic acid is an important compound that contributes to the umami taste. It is often used as a flavor enhancer in various food products.
Amino Acids from Proteins
In addition to the conversion of ATP into inosinic acid, the proteins present in the fish's muscle tissue also undergo changes. Proteins are composed of long chains of amino acids, and after the fish dies, these proteins start to break down into individual amino acids. Two amino acids that are particularly relevant to the umami taste are glutamic acid and aspartic acid.
Glutamic acid and aspartic acid are naturally occurring amino acids that are known for their savory taste. They contribute to the umami flavor by activating specific taste receptors on the tongue, which send signals to the brain, resulting in the perception of umami taste.
Risks to Be Controlled in Aging
Aging Fish Is Not Risk-Free
Aging fish takes a certain amount of time, and different Umami substances increase (or decrease) over different time horizons. It is important to know risks inherent to the process, especially when the fish is ever exposed to temperature abuse.
Microbial Growth
Fish is susceptible to bacterial growth, including harmful pathogens, which can multiply rapidly in the temperature danger zone of 40°F to 140°F (4°C to 60°C). Temperature abuse, such as inadequate refrigeration or extended exposure to higher temperatures, can promote the growth of bacteria and increase the risk of foodborne illnesses.
Spoilage
Fish is prone to spoilage caused by the action of spoilage bacteria and enzymes. Elevated temperatures accelerate the spoilage process, leading to changes in texture, color, odor, and taste. Fish subjected to temperature abuse may develop off-flavors and unpleasant odors, rendering them unappetizing or even inedible.
Histamine Formation
Some fish species, such as tuna, mackerel, and mahi-mahi, contain naturally occurring histidine, an amino acid that can convert to histamine when fish is stored at improper temperatures. Histamine formation can cause histamine poisoning, also known as scombroid fish poisoning, which leads to symptoms such as flushing, headaches, abdominal cramps, and allergic reactions.
Be Sure about Your Fish
To effectively minimize the risks discussed above, it is crucial to have a comprehensive understanding of how the fish has been treated and handled at each point of the supply chain. This involves being knowledgeable about the specific practices and protocols implemented during catching/harvesting, processing, storage, transportation, and distribution of the fish.
We know well about the supplier and develop rigorous management plans of every critical control points according to the HACCP standards of the FDA together with them. We deliver the fresh seafood at the safest level possible, offering the ideal aging potentials.